1. Field of the Invention
Providing configurations and methods to enable mounting vehicle tire chains in one stop of the vehicle, by modifying standard chain configurations and methods, while also providing full chain strength in operation.
2. Prior Art
The time honored method for mounting a tire chain upon the wheel is the roll on method. For that method, the chain is draped over the top of the wheel and a chain end tucked under the wheel, to drive onto. That mounting method is typically specified by chain suppliers.
The system of creating sizes of tire chains for marketing, produces relatively large increments of size between standard sizes of chains. This causes no particular problem when using the roll on method of mounting chains, but causes significant misfits on some tire sizes, when mounting chains about the tire footprint, in order to mount the chain in one stop of the vehicle.
The critical feature is the gap between the end-of-chain cross chains, when mounted on the tire. In general, each chain size covers a range of tire sizes, in which some tire sizes have an end-of-chain gap too small, some just right, and some too large.
One stop mounting, about the tire to ground contact area, is practiced by many chain users, and has the advantage of requiring only one stop of the vehicle for chain mounting. However, in present practice, the above defined problem of end-of-chain gap size is ever present. Thus the mounting conditions are greatly variable, and the smaller tires, within a chain size range, have cross chains deflected much more, and therefore develop much more slack when the wheel moves, eliminating the restraint of the tire footprint. Typically, rubber tightener straps are used to absorb the slack developed in operation, which greatly reduces effective chain strength. Often, an additional stop is required to re-tighten the chains, after initial operation.
The problem at the upper end of a chain size range exists, regardless of mounting method. That is, an oversized end-of-chain gap produces a section of tread without traction enhancement, whether mounted one stop or roll on method.
A lesser problem, but one that applies to all chains, without exception, is the small slack, of up to about two inches, resulting from the need to connect the ends of the outer face side chain. The available accuracy of determining the length of the side chain, fully mounted, is one side chain link pitch. The resulting actual slack cannot be known in advance of the initial chain mounting, due to the variability of tire dimensions, from all sources, including tread wear.
The optimum chain tension, during operation, is not presently known, but it is well recognized, by all users, that some amount of positive chain tension, during operation, is highly desirable. It is generally intended that the rubber straps applied manually provide that tension, but the variables in the use of such straps are large, and stabilization of the chain by steel is much preferred.